Process of making aluminum sulphate from aluminous materials



Patented Dec. 29, 1925.-

'IUNITVED STATES PATIENT "OFFICE,

'RICHABD MOLDENKE, OF WATGHUNG, NEW JERSEY, AND WILI-IELM SCHUMACHER, OF BERLIN, GERMANY SAID SCHUMACHER ASSIGNOR TQ SAID MOLDENK-E.

- rnoc sss or MAKING ALUMINUM 11m FROM ALUMINOUS MATERIALS.

' No Drawing.,

' spectively, have invented a "certain newand useful Improvement in Processes of Making .10, Aluminum Sulphate from Aluminous Materials, of which the following is a specification; i i

'This invention is a process of making aluminum sulphate from aluminous materom the aluminum hydrate. Moreover,"a further and more serious dis- :0

usually considerable quantities of iron compounds present in-the mineral materials under treatment. This iron takes the form of iron sulphate which can only be completely separated from the aluminum sulphateby tedious and costly processes.

.In the present process these disadvantages areovercome in a simple and thoroughly practical manner.

rials such as bauxite, kaolin, clay and'the' advantage resides inthe fact that there are In the preferred manner of practicing this This temperature being above-the boiling point of sulphuric acid'results in the produc I tion of sulphuricacid vapors and the operation is conducted in a closed receptacle.

Any suitable temperature may be em- Application filed January 10, 1923. Serial No. 611,844.

ployed, depending upon conditions, but at these temperatures sulphuric acid will act upon any ferrous oxide Whichmay bepres, ent'but will have practically no effect upon ferric oxide. Accordingly, air is preferablyintroduced into the l treating chamber durng conversion in order. that it may oxidize the ferrous oxide which may be present and change it into ferric oxide. When conver sion is effected inthe manner described, it is found that, while soluble aluminum sulphate is readily formed, the iron which was present in the materials treated will be 7 maintained in an insoluble form and may be readily separated out by subsequent leachmg. I I I The process may be economically practiced by adding another step which consists in taking the aluminum sulphate which re-; sults from the treatment described andcalcining it in a furnace or retort at a suitable to and fed, together with air, into the conversion chamber to act upon the heated material therein. A'saving of sulphuric acid is thereby obtained as the acid is repeatedly used. I

It will, of course,be understood that in carrying out this phase of the process, additional sulphuric acid may be added to the vapors recovered in order that suflicient. vapors may at all times be present to-assurc complete conversion.

Having thus fully described the invention, what we claim as new and desire to secure by Letters Patent, is: 4 1,. The process which consists in subjecting heated aluminous material to the action of sulphuric acid vapors, to produce alu-" minum sulphate, and introducing air to oxi- 2. The process which consists in, subjecting aluminous-materials to the action of sulphuricacld vapors and airwhile maintaining a; temperature above'the' boiling point of sulphuric vacid and above the temperatures atwhich the sulphuric acid will-ap-- preciably act upon. ferric oxide.i r

. 3. The'processwhich consists in -subjectg in'g aluminous materials to theaction of's'u-1 phuric acid vaporsand'air'while maintainsulphate,"in the presence 1 of air" to oxidize the iron contained in said materials, therer after leaching out-the 'alummum sulphate,

thereafter calcining the aluminum sulphate.

todrive. o'fi sulphuric acid vapors therefrom and utllizing such acid vapors to treat further aluminous mater als. a

- v 5. The process which consists'in subjectngaluminous materials to the action of sulphuric acid vapors and air to producealuminum sulphate, then leaching out the alliminum sulphate, thereafter calcining the aluminum sulphate to drive ofi' sulphuric acid vapors therefrom, and utilizing such rials.-

acid vapors to treat further aluminous mate- 6. The process which consists in subjecting alummous materials to the action-of sulphuric acid vapors and a r While maintaining a temperature above the boihng point of sulphuric acid and above the temperatures at which the sulphuric acid will appreciably aifect ferric oxide, for the purpose of producing aluminum sulphate,.'tl1en leaching out thealuminum sulphate thei'eafter calcining said aluminum sulphate to 1 drive oif sulphuric acid vapors" therefrom, and utilizing such vapors with further fair to treat additional aluminous materials.

foregoing specification.

' RICHARD MOLDENKE.

WTLHELM so U oHE 35 w In testimony whereof We have-signed the 

